"for the question how did canadas policy of total war change the economy? why was the policy necessary?

for this one i wrote that canada manufacture lots of things like military vehicles, tanks. Ships for navy, new planes, and bombers, military vehicles and tanks, munitions factories. As well as farmers were producing more wheat, beef dairy products and other foods for the war effort. there was increase in supply and demand. and for how policy changed that be they were more involved in the war?"

Canada's policy of "total war" was to do everything possible to help the Allies. As you said, it manufactured many weapons and vehicles. It produced more food to help the war effort. By doing that, more people had good-paying jobs, so Canada's economy improved.